Wind farm and method for operating a wind farm

Abstract

A method for operating a wind farm comprising several wind turbines that are connected to an internal grid of the wind farm is disclosed. In the method, during a mains failure the electrical consumers of the wind turbines are supplied with electrical energy by a mains replacement supply unit. Each electrical consumer of the wind turbines is assigned to one of at least two groups and according to the group assignment is always switched on by an operation control unit when required, or only switched on if there is a sufficient power reserve. The wind farm is designed to carry out the method.

The invention claimed is: 
     
       1. A method for operating a wind farm having a plurality of wind energy installations connected to a grid internal to the wind farm, each having an operating control unit and other electrical components comprising electrical consumers, and a mains substitute supply unit connected to at least some of the electrical consumers of the wind energy installations, wherein the electrical consumers of each wind energy installation are divided into at least two groups comprising a first group and a second group, at least consumption values of the electrical consumers of the second group are stored in the operating control unit of the wind energy installation concerned, the electrical consumers can be switched on and off by the operating control unit of the wind energy installation concerned when requested, and the operating control unit has a grid fault mode in which a power reserve is calculated from a maximum consumption value of the wind energy installation concerned and actual consumption of the electrical consumers that are switched on, comprising:
 switching, by the operations control unit, one of the electrical consumers of the first group on when requested, 
 switching, by the operations control unit, one of the electrical consumers of the second group on when requested and when the power reserve is greater than or equal to the consumption value of the requested electrical consumer, and 
 changing operating parameters of one of the wind energy installations when in grid fault mode. 
 
     
     
       2. The method of  claim 1 , wherein when the consumption value stored in the operating control unit for a requested electrical consumer of the first group is greater than the power reserve, one or more electrical consumers of the second group are switched off. 
     
     
       3. The method of  claim 1 , wherein when an actual consumption is greater than the maximum consumption value, one or more electrical consumers of the second group are switched off. 
     
     
       4. The method of  claim 1 , wherein a farm master is connected to the operating control units and transmits the maximum consumption value to the operating control units. 
     
     
       5. The method of  claim 4 , wherein the maximum consumption value is calculated from a specified value of the maximum power of the mains substitute supply unit, a base load, and the number of wind energy installations in the wind farm. 
     
     
       6. The method of  claim 4 , wherein the operating control units transmit the actual consumption and requests for switching on electrical consumers to the farm master, and the farm master, on the basis of this information, reduces the maximum consumption value of one or more wind energy installations for a short period, while simultaneously the maximum consumption value of one or more wind energy installations is increased. 
     
     
       7. The method of  claim 1 , wherein the actual consumption is measured or calculated on the basis of consumption values for the electrical consumers of the first and second groups stored in the operating control unit. 
     
     
       8. The method of  claim 1 , wherein the operating control unit in grid fault mode switches off electrical consumers of a third group of the at least two groups. 
     
     
       9. The method of  claim 1 , wherein at least one wind energy installation continues to be operated in grid fault mode, so that it feeds electrical power into the grid internal to the wind farm. 
     
     
       10. A wind farm comprising:
 a plurality of wind energy installations connected to a grid internal to the wind farm, each having an operating control unit and other electrical components comprising electrical consumers, and 
 a mains substitute supply unit connected to at least some of the electrical consumers of the wind energy installations, 
 wherein the electrical consumers of each wind energy installation are divided into at least two groups comprising a first group and a second group, at least consumption values of the electrical consumers of the second group are stored in the operating control unit of the wind energy installation concerned, the electrical consumers can be switched on and off by the operating control unit of the wind energy installation concerned when requested, the operating control unit has a grid fault mode in which a power reserve is calculated from a maximum consumption value of the wind energy installation concerned and actual consumption of the electrical consumers that are switched on, the operating control unit switches one of the electrical consumers of the first group on when requested and switches one of the electrical consumers of the second group on when requested and when the power reserve is greater than or equal to the consumption value of the requested electrical consumer, and operating parameters of one of the wind energy installations are changed when in grid fault mode. 
 
     
     
       11. The wind farm of  claim 10 , wherein a plurality of electrical consumers are connected via a busbar. 
     
     
       12. The wind farm of  claim 10 , wherein when the consumption value stored in the operating control unit for a requested electrical consumer of the first group is greater than the power reserve, one or more electrical consumers of the second group are switched off. 
     
     
       13. The wind farm of  claim 10 , wherein the mains substitute supply unit is connected to at least some of the electrical consumers via the grid internal to the wind farm. 
     
     
       14. The wind farm of  claim 10 , comprising one or more power contactors configured to switch electrical consumers on and off.